Arrangement for openings in scanning disk-multiple cardioid



Sept. 13, 1932.

R. w-. ARMSTRONG ,877,547

ARRANGEMENT FOR OPENINGS .IN SCANNING DISK MULTIPLE CARDIOID Filed May 28, 1950 2 Sheets-Sheet 1 4 a I a 5 8 5 7 9 y la I ll a2 as as a? 25 I3 4 I4 7 49 a? 2s 38 I 5a 55 F7922. as. 47

6 30 I v v a2 so 4/ l8 3 5 E9 27 /6 KNVENTOR 40 Ralph WArmsTrqng.

ATITOIRNEY Sept. 13, 1932.

R. W. ARMSTRONG ARRANGEMENT FOR OPENINGS IN SCANNING DISK MULTIPLE CARDIOID Filed May 28, 1930 2 Sheets-Sheet 2 20 INVENTOR 44 fialplr WAr/ns fro/19.

Patented Sept. 13, 1932 UNITED STATES PATH A RALPH w. ARMSTRONG, oE-wILKINsEn G, PENNSYLVANIA. ASsIGNoR .To wEsTIN i HOUSE ELECTRIC & MANUF CTURING coMPANY, A CORPORATION OF PENNSYL- VANIA ARRANGEMENT RoR OPENINGS IN sCANNING DISK-M LTIPLE CARnIoID Application filed May as,

My invention relates to television systems and more particularly to methods of scanning and means whereby such methods may be efficiently practiced.

In television systems constructed and arranged according to the prior art, scanning is generally accomplished through the use of such instrumentalities as rotating disks,

; vibrating mirrors or the like which are designed to cause a light beam to pass over the subject to be televised in a predetermined manner. Insofar as I am aware, whichever instrumentality is utilized, the predetermined manner of scanning takes place in one direction only; that is, the beam of light may be Caused to traverse horizontal elements of the subject, beginning with an element at the top of the subject, travelling downwardly to the bottom element and then repeating the operation.

At the receiving end of such system, a similar scanning device must be employed, with the result that this uni-directional scanning method presents to the eye of an observer a water-fall effect as the beamof light at the receiving end travels downwardly, in translating the transmitted im pulses of the televised subject, to produce the image of the same. The above effect is very undesirable, as it impairs the detail and visibility of received pictures. A

It is, accordingly, one object of my invention to provide an improved scanning method to be followed at either the transmitting or the receiving end of atelevision system to eliminate the water-fall effect referred to above. a V Another object of my invention isto provide a scanning means whereby the above method may be put into practice. I

Additional objects will be disclosed in the following description of my invention.

I have discovered that excellent results may be obtained by a scanning procedure which comprises the scanning of the subject in a non-sequential fashion and the Chang ing of the direction of scanning. For example, I might scan alternate horizontal elements of the subject in succession, from top to bottom, and then, instead of following the 1930. Serial No. 456,521.

usual procedure of repeating the contemplate scanning the. unscanned elements of the sub ect n reverse order,.that is,

from the bottom to the. top ofthe subject.

In this manner, break up theuni-dire ctional Scanning sequence of adjacent elements ,of a

televisioned subject, these being the. chief.

causes of the water-fallefiect.v

My improved methodmaybe applied to any of the scanning devices referred toabove which, of course, may be modified for the Purpose; Inthe scanningv arrangement utilizing vibratingmirrors, it. is apparent that the relative motions of the mirrors may be .1:

cordingto my improved method. As another means whereby my method nay be put into use, I have provided a scanning so adjusted as to accomplish scanning lacdevice of the disk type, wherein the scanning elements are so arranged as to accomplish the desired result. arrangement of scan ning, elements very suitable for. the purpose comprises .afcardioid' arrangement made up of two spirals or multiples thereof, running disclosed in the accompanying drawings wherein Figure 1 represents a simplified embodi ment of my scanning device.

Figs. 2, thereof. j o i Referring more particularly a to Fig. 1,. I

have illustrated ascanning disk of 6'0 scan 3 and 4 represent modificationsning elements,in the form ofasing lecardioid, comprising a pair of spiralsrunning 1n opposite directions. ments of one spiral are so spaced from the edge of the disk as to scan alternate scanning elements on a subject, the scanning elements The, scannin 1 comprising'the other spiral'being" so spaced I from the edge as to scan the" remaining elements. Employing the arrangement disclosed in Fig. 1, it will be apparent that substantially no two adjacent picture elements will be scanned successively, and various elements will be scanned at equal time intervals. The above condition, or conditions approximating them, are essential in the accomplishment of the desired results for, when ever a plurality of adjacent subject elements are successively scanned, a light fiutter or the aforementioned waterfall effect will be the result.

I have found that improved results may be secured by the use of a disk, wherein the arrangement of the scanning elements comprises a plurality of oppositely directed spirals, as illustrated in Fig. 2. The particular spacing of the elements is obtained through a mathematical relationship derived from the species disclosed in Fig. 1, the results of which may preferably be modified in an arbitrary manner to obtain'more efficient operation. q I i 14% equals the number of cardioids comprising the arrangement of scanning elements on the disk, then the scanning elements on the single cardioid disk determined by the progression 1, n+1, 2n+1, etc., 2, n+2, 2701 2, etc., will determine the order of scanning of the a cardioid disk.

As an illustration, let it be assumed that it is desired to construct a'six cardioid 6O scanning element disk. To determine the order in which the scanning elements should ap pear thereon, the above mathematical progression is applied to the single cardioid arrangement of Fig. 1. For example, n+1 equals 7. The 7th scanning element on the single cardioid disk is element 13. Therefore, element 13 will follow the scanning element 1. In like manner, 2n+1 equals 13, which corresponds to .the scanning element 25 on the single cardioid. Therefore, element 25 will follow element 13. Developing the above calculations, the following order of scanning is obtained:

The scanning order obtained by the mathematical method outlined above serves 'to break up the scanning sequence followed by the scanning arrangements of the prior art and also serves to change the direction of scanning; that is, the horizontal light lines I travel upwardly as well as downwardly, all

tending to eliminate the light effects referred to above. It will be noted, however, that certain of the adjacent. scanning lines in the above order, i. e., 1 and 2, 10 and 9, 4 and 5, 55 and 54, follow successively thereby, to a small degree, tending toward the production of local light flutter. To overcome this I resort to arbitrary means and interchange the locations of the above elements to more widely separated positions in the order of scanning, thereby obtaining an arrangement as follows:

1, 13, 25, 37,49, 56, 48, 36, 24, 12-9, 19, 31, 4.3, 59, 54,12, 30, 1s, 5-5, 15,27, 59, 51, 58, 4e, 94, 22, 107, 21, e5, 15, 57, 52, 40, 28, 16, 2 5, 17, 29, 41, 53, 60, 44, 52, 20, e 11, 29, 35, 47, 55, 50, 38,26, 1 4,1.

Fig. 2 of the drawing represents a cordioid disk embodying the above scanning arrangement.

Various other methods of schemes may be then space the successive elements by steps of 12 scanning lines for theleft-hand spirals. By averaging the successive numbers of preceding left-hand spirals, I can determine the order ofthe scanning elements comprising the right-hand spirals. The following scanning order is obtained as a result of utiliz} ing the above scheme: i

Scanning elements 12 and 13, 24 and 25, which appear close together in the above or der,may be shifted to obtain improved results. For example, 16 and 12 might be interchanged and 28 and 24 might be reversed as to position. The resultant scanning order is embodied in the disk disclosed in Fig. 3.

Another scheme which I have worked out for obtaining an efficient scanning disk is to arbitrarily assign elements 1, 4, 2, 5, 3, 6 as the starting elements of the cardioids l, 2, 3, 4, 5 and 6, respectively, of Fig. 4 and elements 58, 55, 59, 56, 60 and 57 as the terminating elements of the cardioids and then I decrease the intermediate elements in steps of 12 scanning lines to obtain the'following scanning order:

It will be apparent that various other mathematical or arbitrary-schemes may be resorted to, to obtain an arrangement of scanning elements for breaking up the sequence of scanning and altering the direction of scanning of the scanning arrangements of the prior art and, therefore, While I have disclosed my invention in great detail, I do not desire to be limited except insofar as shall be necessitated by the prior art and the appended claims.

I claim as my invention:

1. The method of scanning a picture in a television system comprising scanning certain of the picture elements throughout the Whole picture in one direction and thereafter scanning the other elements in another direction.

2. The method of scanning a picture in a television system comprising scanning nonadjacent elements of the picture throughout the Whole picture in one direction and thereafter scanning the remaining elements in the opposite direction.

In testimony whereof, I have hereunto subscribed my name this 22nd day of May 1930.

RALPH W. ARMSTRONG. 

